Firewall: The ubiquitous-to-the-point-of annoyance political word for a state, region or group of supporters that serves as an all-important barrier against disaster.

“Firewall” dates from 1851 and originally referred to an actual structure that could protect against encroaching flames. In computers, it’s a traffic-monitoring security system. But it has completely been usurped by presidential politics these days as the horse race thunders along, because it’s both punchy and vaguely authoritative-sounding.

“The emergence of the word ‘firewall’ everywhere is very ‘Veep’-like,” Washington Post political writer David Weigel recently observed on Twitter, a reference to the Emmy Award-winning HBO comedy that so wickedly and accurately mocks Washington convention.

“Firewall” is, indeed, everywhere. Fox News’ Howard Kurtz wrote a piece this week headlined, “The media’s firewall against Donald Trump: The voters must be dummies or racists.” Buzzfeed did another one: “Ted Cruz’s Southern Firewall Turns Into a Danger Zone.” Politico Magazine, in an article about South Carolina’s historic importance as a GOP sorter of serious candidates, also used the term.

And before Hillary Clinton prevailed in Saturday’s Democratic caucus in Nevada, news outlets referred to the Silver State and its relatively large concentration of Hispanic voters again and again – and then some more – as her firewall.

Candidates themselves can be firewalls, too. Pollster John Zogby wrote in Forbes that Senator Marco Rubio’s Hispanic background is a huge asset to Republicans: “After yesterday’s results in Nevada, we see that Hispanics will vote in big numbers in 2016. And they will come out to vote against Trump. Rubio is the firewall. He cannot win against a Democrat among Hispanics, but he could stop some bleeding.”

Complaints about “firewall” actually have surfaced in other campaigns. Back in 2008, the now-defunct media magazine American Journalism Review cited it as one of three particularly overused pieces of pundit jargon, along with “moving the goalposts” and “Kumbaya.” Veteran journalist Rick Dunham dubbed it one of the worst political clichés of 2012.

But in this race, pundits have had a new excuse to pull it out – as a humorous pairing with “feeling the Bern” in reference to Mrs. Clinton’s rival for the Democratic nomination.